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McCain is a strong critic of Trump

This isn't the first time he criticized Trump on Saturday

Washington (CNN)Sen. John McCain slammed President Donald Trump on Saturday for saying he believes Russian President Vladimir Putin over senior US intelligence officials when he says his country didn't interfere in the 2016 election.

"President Trump today stated that he believed Vladimir Putin is being sincere when he denies Russian interference in the 2016 presidential election and reiterated that he hopes to cooperate with Russia in Syria," McCain, a strong critic of the President, said in a statement. "There's nothing 'America First' about taking the word of a KGB colonel over that of the American intelligence community. There's no 'principled realism' in cooperating with Russia to prop up the murderous Assad regime, which remains the greatest obstacle to a political solution that would bring an end to the bloodshed in Syria. Vladimir Putin does not have America's interests at heart. To believe otherwise is not only naive but also places our national security at risk."

McCain was referencing remarks Trump made while describing his relationship with Putin and the ongoing investigations into 2016 meddling on Saturday. The president seemed to indicate to reporters aboard Air Force One on Saturday that he trusts Putin's denials more than the comments of former intelligence officials, like former high-ranking intelligence officials James Comey, John Brennan and James Clapper.

"I mean, give me a break, they are political hacks," Trump said. "So you look at it, I mean, you have Brennan, you have Clapper and you have Comey. Comey is proven now to be a liar and he is proven now to be a leaker. So you look at that and you have President Putin very strongly, vehemently says he had nothing to do with them."

Trump defended his decision on the plane with reporters, saying he is addressing human rights but also "many other things."

"Well, I do do it. But I also raise issues on many other things," he said. "I mean I have an obligation -- we lost last year with China, depending on the way you do your numbers, because you can do them a number of ways, anywhere from $350 to $504 billion. That's with one country."

McCain has stepped up his criticism of Trump in recent weeks. Last month, he warned against "half-baked, spurious nationalism" while accepting the Liberty Medal from former Vice President Joe Biden.

The Vietnam veteran, who was tortured during his more than five years as a prisoner of war, also appeared to mock Trump's draft deferments when he criticized people from "the highest income level" who avoided the draft by finding a doctor who "would say that they had a bone spur." He later said the comment was not specifically about Trump.